A strong challenge by a lower court judge who contended there were too few blacks on the Baltimore Circuit Court threw two sitting judges into a tight battle to hang on to their seats last night, while a third sitting judge, Ellen L. Hollander, easily retained her seat on the Circuit Court.

Meanwhile, sitting judges in Wicomico and Howard counties easily beat back challenges to win new 15-year terms on the state's circuit courts.

In Baltimore, Judge Hollander quickly took a controlling lead in the judicial contest and steadily widened the gap as the evening wore on. But with 88 percent of the vote counted, the other two sitting judges, Richard T. Rombro and John C. Themelis, were locked in a close race with their principal challenger, District Judge Paul A. Smith. The contest was neck and neck when city elections officials stopped counting the remaining ballots because of problems in reading vote tallies.

Judge Hollander, 41, was originally thought to be the most vulnerable of the three sitting judges, but she ran a surprisingly -- strong race and was easily outpolling her two male colleagues. The former assistant U.S. attorney was the only woman running for judge in the city.

Meanwhile, in Howard County, Judge James B. Dudley, handily defeated his challenger, attorney Jo Ann C.W. Branche. Judge Dudley, who was appointed last year, sounded the experience theme in his campaign, while Ms. Branche said her campaign gave voters a chance to participate in the selection of judges.

In Wicomico County, Judge Richard Dexter Warren, who was appointed in September 1988, survived a challenge by Don E. Richardson.

As the polling began in Baltimore yesterday, the three sitting judges ended a nearly two-year campaign in which they crisscrossed the city pointing to the fact they had undergone a rigorous selection process before being appointed by the governor. The three judges, all white, faced two black challengers.

It proved to be one of the most sharply contested courthouse elections in years. Judge Smith pointed to his seven years on the District Court bench and ran a campaign in which he cast himself as being more experienced than the Circuit Court judges.

Baltimore attorney Frederick P. Charleston, a late-comer to the judicial race, ran a campaign in which the central issue was the representation of African-Americans on the Circuit Court. Though the city has a majority black population, only seven of the 24 circuit judges are black.

While the five-way race for the Circuit Court judgeships drew intense attention, it was not the only contest this year at the Circuit Court. Saundra E. Banks, the incumbent court clerk, defeated challenger William Allen by an overwhelming margin. On the Orphans' Court, incumbent Judges Michael W. Lee, Howard I. Golden and David B. Allen were challenged by Baltimore lawyer Lance O. Brown. With 84 percent of the vote counted, Judge Allen held a comfortable lead and appeared well on the way to retaining his seat. But Judges Lee and Golden held only slim leads over Mr. Brown in a race for the two other Orphans' Court judgeships.

In the city sheriff's race, w Sheriff John W. Anderson appeared to have defeated challengers Beatrice Brown and James E. Brewer.